The Ring Expansion – Ring Contraction Dichotomy in Aromatic Nitrene and Carbene Reactions I. Arylcarbenes. Preliminary communication

Rearrangement experiments and energy calculations by the CNDO/2 and extende Hückel methods indicate that ring expansion and ring contraction in aromatic carbenes and nitrnes can be one‐step processes which are governed by the stabilities of the primary products and the energies of the reactants.